Neurologic complications after primary anatomic or reverse total shoulder arthroplasty

Background: The incidence of the various types of neurologic complications that can occur after primary shoulder arthroplasty, as well as the factors associated with these complications, are unclear. Methods: We reviewed 309 cases of primary anatomic total shoulder arthroplasty (TSA) and 504 cases of reverse TSA performed from 2003–2017 with minimum 1-year follow-up. We defined 3 types of neurologic complication: iatrogenic nerve injury, new-onset compressive peripheral neuropathy (CPN), and worsening of preexisting CPN. Multivariate analyses were performed to identify factors associated with each type of neurologic complication. Results: The overall rate of neurologic complication after primary shoulder arthroplasty was 16% (127/813) (95% confidence interval [CI]: 13%–19%). The rates by complication type were 10% (81/813) for iatrogenic nerve injury, 18% (39/216) for worsening of preexisting CPN, and 1.8% (15/813) for new-onset CPN. The incidence of the 3 complication types did not differ between anatomic and reverse TSA. All cases of iatrogenic nerve injury improved without operative treatment after 1 year, whereas 53% of cases of new-onset CPN and 36% of cases of worsening CPN required surgical release. We found no factors independently associated with iatrogenic nerve injury, but iatrogenic nerve injury was independently associated with new-onset CPN. Factors independently associated with worsening CPN were male sex and a history preexisting CPN not treated with previous surgery. Conclusion: Nearly 1 in 5 patients experienced neurologic complications after primary shoulder arthroplasty. Clinicians should be alert for neurologic symptoms because some patients develop CPN or worsening of CPN that may warrant surgical treatment. Level of Evidence: Level IV; Retrospective Cohort; Treatment Study